Questions for Secondary Mail Server in Virtualmin Pro

OS type and version Ubuntu Linux 22.04.1
Webmin version 2.001
Virtualmin version 7.3-1
Related packages Postfix

I see you now have the ability to add a Secondary Mail Server in Virtualmin Pro.
*You caught my eye on this feature!

My questions for this feature are:

  1. Does the second server need to be Virtualmin pro version? I only need it as a secondary mx server.
  2. Does the first server automatically send the second server the map for the domains? Do I have to copy them over?
  3. Would like to know if this feature could be used to set the second server as the main email server? If not, this feature would be great for those who have port 25 blocked on main server. Just open a secret port for servers to connect through relay and receiving.



No. There are very few Pro-only features related to mail, and the secondary mail server setup is just a hold and forward thing…so it’s using very little of the mail stack. It may not even need Virtualmin, I don’t remember how it works exactly. But, if it knows about users (probably does) it would need Virtualmin, but GPL should be fine.

I don’t recall, but if it knows about users, I’m sure it syncs them. Been a while since I set it up…

I don’t understand the question. You can’t tell the rest of the world to use other ports, secret or otherwise. If you don’t have port 25 you do not have a mail server…you’ll need some server to accept mail for you and forward it on a different port.

If your secondary has port 25, it can, of course provide the forwarding, but I tend to recommend you just put everything on a real server that has all the ports, if you want to host email. It gets complicated when you add relaying and forwarding, and this feature isn’t really related to that. It’s just intended to allow a sever to operate as a backup MX, so that during downtime (whether scheduled or otherwise) the secondary can accept the mail and then keep trying to forward it until it comes back online. You can of course configure it to relay on the submission port rather than SMTP. You control both servers, so you can tell your hold and forward server to do whatever you want.

Thank you for the quick response!

Third question only relates to your main server relaying to the second server. I have clients who had set up a server and come to find out that the data center doesn’t allow the use of port 25. So this results in setting up and customizing postfix to relay on port 2525 between another postfix server that allows for port 25. We just need to copy the email maps over to the other server being used for email.

The end results allows the email server to have its own dedicated resources. It works and everybody is happy happy…

Just needed to know how you are connecting both servers so that it can automatically read the maps.